A distributed braking system for an automobile

Abstract

The present invention discloses a distributed braking system for an automobile, which is composed of a liquid storage tank, a brake pedal, a master cylinder, an electromagnetic isolation valve, a two-position three-way valve, a pedal force simulation device, a pedal controller, a main brake controller, a front-wheel servo brake cylinder, a rear-wheel side brake / rear-wheel servo brake cylinder, sensors and brake wheel cylinders. In the present invention, the front-wheel servo brake cylinder and the rear-wheel side brake / rear-wheel servo brake cylinder are close to the brake wheel cylinders, with a short decompression time and a fast braking response. There is no solenoid valve in the pressure building circuit of the servo brake cylinder, and a motor is directly used for brake pressure building, making the pressure building more direct and the adjustment simple. There are multiple actuators, enabling the braking forces of all wheels to be independently controlled and adjusted. Each actuator is located at the wheel side of each wheel, reducing the hydraulic transmission distance and increasing the pressure building speed. The hole positions and cylinder block design of the servo brake cylinder can ensure that the main cylinder infusion holes are not blocked in the manual backup mode, avoiding the failure of the manual backup.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive autonomous driving, and particularly to a distributed braking system for an automobile. Background Art

[0002] From the perspective of the requirements of autonomous driving for the braking system, intelligent driving at all levels requires that the vehicle be equipped with an autonomous braking function, that is, to apply brakes to all or part of the wheels when the driver does not operate the braking control device. Currently, the devices that can implement autonomous braking mainly include electronic hydraulic braking (EHB), electro-mechanical braking (EMB), the hydraulic control unit of electronic stability control (ESC), and various electro-hydraulic servo braking systems, etc.

[0003] EHB generally uses a high-pressure liquid storage tank as an energy supply device, whose pressure is generated by an electro-hydraulic pump and can implement active braking when necessary. During braking, the brake fluid in the high-pressure liquid storage tank is introduced into the master cylinder to push its piston or directly delivered to the wheel cylinder, and the braking pressure of the wheel cylinder is adjusted by the control device. A pedal travel simulator is used to provide the driver with the feeling of the brake pedal (i.e., the so-called "road feeling"), and it has the function of manual backup braking. When the EHB system fails, a backup manual hydraulic braking system is used. Such a braking system is not very compact due to the need for a high-pressure liquid storage tank and an additional backup hydraulic system. The high-pressure liquid storage tank enables the braking system to quickly build up the braking pressure and can shorten the braking distance, but in the event of a collision or the like, it may cause high-pressure leakage and pose a threat to the safety of the occupants, presenting a safety hazard. In addition, the pump and its drive motor for the high-pressure liquid storage tank need to work frequently even when not braking, and their service life is affected.

[0004] The actuators of the EMB are dispersedly arranged near each wheel and belong to a type of distributed braking system. The distributed braking system has many advantages and is considered the development direction of the next-generation braking system. Since the braking forces of all wheels can be independently controlled and adjusted, the distributed braking system has the advantages of flexible control and high braking force control accuracy; the actuators of the distributed braking system are close to the wheel brakes, so the braking response is fast and the dynamic characteristics of the braking pressure are good; compared with the traditional dual-circuit braking system, the distributed braking system with four-wheel independent braking is equivalent to a "four-circuit" system, further improving the reliability of the system. The EMB system generally relies on a control device to control a motor to drive a speed reduction and torque increase conversion mechanism, etc., and directly presses the brake pads of the brake against the brake disc to generate braking force. Since there is no need for brake fluid and hydraulic pipelines, the EMB system has the advantages of short initial pressure establishment time and fast dynamic response of the brake, even exceeding that of the EHB relying on the hydraulic pump to output hydraulic pressure. Major global automotive component companies such as Continental Teves in Germany, Siemens in Germany, and Delphi in the United States have successively developed their respective EMB prototype models. Such a braking system requires a complex mechanical conversion structure to generate braking force. Although the response speed is fast, the failure protection ability is difficult to gain the trust of automotive manufacturers. After adopting the EMB, the traditional brakes cannot be used continuously, and new brakes and high-performance power sources need to be developed, resulting in a relatively high manufacturing cost. For these reasons, the EMB has not been applied to mass-produced vehicles so far.

[0005] Although vehicles equipped with anti-slip regulation (ASR) and ESC based on differential braking can implement active braking through their hydraulic control units (HCU), the pressure establishment time is relatively long, and since its solenoid valves are not suitable for continuous operation for a long time, it is difficult to meet the autonomous braking requirements of intelligent driving vehicles. Another disadvantage of such a hydraulic control unit is that it makes a relatively large noise when working, as it uses a plunger pump to implement active braking.

[0006] There are many types of electro-hydraulic servo braking systems that can implement autonomous braking. For example, Chinese Patent CN203753122U discloses an automatic hydraulic braking system for realizing intelligent driving, which adds a solenoid valve group controlled by a braking control computer between the master cylinder and the ESC to the HCU. After this solenoid valve group is installed in the original vehicle hydraulic braking system, it meets the braking requirements for both manual driving and driverless driving, and the two states of manual braking and autonomous braking can be switched. However, due to the long braking pipeline, it is not conducive to quickly establishing the braking pressure and the braking response is slow; in the autonomous braking mode, this structure does not support slow pressure relief, and the solenoid valve group cannot achieve pressure follow control, so the pressure regulation accuracy of the braking system is not high and the motion smoothness of the vehicle during autonomous braking is relatively poor.

[0007] In addition to the above braking system, the distributed braking system further includes a distributed electro-hydraulic braking system. Chinese Patent Application CN102700538A discloses an automotive distributed electro-hydraulic braking system, which is provided with four groups of distributed solenoid valves and a pedal travel simulator in its structure, and has a failure manual backup braking function and a braking mode reconstruction function. When all wheel braking actuators of the system cannot provide braking hydraulic pressure, all solenoid valves remain de-energized, and the driver can implement manual backup braking; when only some wheel braking actuators of the system fail, the braking mode can be reconstructed to implement braking on all wheels; when the system is working normally, the braking pedal feel is provided by the pedal travel simulator, and the system operates in a by-wire mode. The main disadvantages of this system mainly include: due to the adoption of distributed multiple groups of solenoid valves, the structure is complex and the cost is high; the controller management is relatively centralized, and when the controller fails, the entire system will directly enter the failure backup state, and the functional safety is not perfect enough. Summary of the Invention

[0008] Aiming at the deficiencies of the prior art, the present invention aims to provide a distributed braking system for an automobile.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] A distributed braking system for an automobile, which consists of a liquid storage tank, a braking pedal, a manual cylinder, an electromagnetic isolation valve, a two-position three-way valve, a pedal force feel simulation device, a pedal controller, a main braking controller, a front-wheel servo braking cylinder, a rear-wheel side brake, sensors and a brake wheel cylinder. The sensors include a pedal travel sensor, a master cylinder pressure sensor, an inertial measurement unit, a wheel cylinder pressure sensor, a wheel speed sensor and a force sensor;

[0011] The braking pedal is connected to a piston in the manual cylinder, and the manual cylinder is connected to the liquid storage tank through a hydraulic pipeline; the manual cylinder is connected to the electromagnetic isolation valve through a hydraulic pipeline, the electromagnetic isolation valve is respectively connected to the pedal force feel simulation device through a hydraulic pipeline, and the pedal force feel simulation device and the front-wheel servo braking cylinder are connected to the liquid storage tank through a hydraulic pipeline; the two-position three-way valve is respectively connected to the manual cylinder, the liquid storage tank and the front-wheel servo braking cylinder through a hydraulic pipeline; rear-wheel side brakes are respectively arranged on the wheel sides of the two rear wheels, and brake wheel cylinders are respectively arranged at the wheel ends of the two front wheels and the two rear wheels; each front-wheel servo braking cylinder is connected to the brake wheel cylinder of the corresponding front wheel through a hydraulic pipeline;

[0012] The pedal travel sensor and the master cylinder pressure sensor are respectively used to detect the travel data of the brake pedal and the pressure data of the master cylinder; the inertial measurement unit is used to monitor the acceleration and angular acceleration of the vehicle in all directions; the wheel cylinder pressure sensor is used to measure the pressure data of each front-wheel servo brake cylinder; the wheel speed sensors are respectively used to measure the wheel speed data of the tires; the force sensors are used to measure the braking force of the rear-wheel brakes on both rear wheels; the controllers of each front-wheel servo brake cylinder are respectively connected to the wheel cylinder pressure sensor and the wheel speed sensor corresponding to the front wheel through signal lines, and the controllers of the rear-wheel brakes on both rear wheels are respectively connected to the wheel speed sensors and the force sensors corresponding to the rear wheels through signal lines;

[0013] The pedal controller is respectively connected to the pedal travel sensor, the master cylinder pressure sensor, the electromagnetic isolation valve, the two-way three-way valve, the controllers of the front-wheel servo brake cylinders and the controllers of the rear-wheel brakes on both rear wheels through signal lines. The brake master controller is respectively connected to the controllers of the front-wheel servo brake cylinders and the controllers of the rear-wheel brakes on both rear wheels through signal lines. The pedal controller and the brake master controller are connected through a data bus.

[0014] Further, the rear-wheel brakes on both rear wheels adopt electromechanical brakes.

[0015] Further, the front-wheel servo brake cylinder includes an electric cylinder housing, a ball screw, a nut, a return spring with preload, a guide pin and a motor; the electric cylinder housing forms a first cavity and a second cavity isolated from each other through a piston. The ball screw and the nut are arranged in the first cavity of the electric cylinder housing. The nut is matched with the ball screw. The motor is connected to the ball screw and can drive the ball screw to rotate. The ball screw can drive the nut to move linearly; the return spring is arranged in the second cavity of the electric cylinder housing, and its two ends respectively abut against the piston and the inner wall of the electric cylinder housing; four holes for the flow of brake fluid are arranged on the electric cylinder housing; the first hole is communicated with the second cavity of the electric cylinder housing and forms a braking circuit with the brake wheel cylinder; the second hole is used for installing the wheel cylinder pressure sensor to supply the controller to collect the circuit pressure; the third hole is a liquid replenishing hole and is used to be connected to the liquid storage tank; the fourth hole is a backup hole, which is communicated with the first cavity of the electric cylinder housing and is connected to the master cylinder through a two-way three-way valve; the guide pin is used to limit the nut from rotating in the first cavity of the electric cylinder housing.

[0016] The present invention also provides a working method for the above system, and the specific process is as follows:

[0017] During normal operation, when the driver steps on the brake pedal, the pedal controller controls the electromagnetic isolation valve to conduct, and the two-way three-way valve conducts the liquid storage tank and the front-wheel servo brake cylinder, so that the brake pedal and the pedal force simulation device are conducted, and the driver obtains the pedal force through the pedal force simulation device; the brake master controller obtains the stroke data detected by the pedal stroke sensor and the pressure data measured by the pressure sensor from the pedal controller, and based on this, identifies the driver's braking intention, and then transmits the command to the controllers of the front-wheel servo brake cylinder and the rear-wheel side brake through an electrical signal to control their respective boosting actions, so as to obtain fast and uniform braking force;

[0018] When the pedal controller fails, the electromagnetic isolation valve closes, and the two-way three-way valve conducts the master cylinder and the front-wheel servo brake cylinder, and the driver's pedal force can be transmitted to the front-wheel servo brake cylinder; at this time, the brake master controller obtains the driver's braking intention according to the pressure data measured by the wheel cylinder pressure sensor of the front-wheel servo brake cylinder; the brake master controller controls the rear-wheel side brake to perform a certain degree of braking force control according to the driving intention to achieve a greater braking force than in the case of total failure;

[0019] When the brake master controller fails, the system will not be able to communicate with other controllers of the vehicle, but the driver's intention can still be obtained by the pedal controller; at this time, the controllers of the front-wheel servo brake cylinder and the rear-wheel side brake still communicate with the pedal controller to jointly achieve braking control;

[0020] The controllers of the front-wheel servo brake cylinder and the rear-wheel side brake are redundant to each other. Therefore, when one or more of the controllers of the front-wheel servo brake cylinder and the rear-wheel side brake fail, the brake master controller will coordinate the remaining front-wheel servo brake cylinders and rear-wheel side brakes that can still work to perform braking and balance the yaw torque.

[0021] Furthermore, in the above method, the controllers of the front-wheel servo brake cylinder and the rear-wheel side brake can be powered by multiple independent power supplies; when the controllers of the front-wheel servo brake cylinder and the rear-wheel side brake are all powered off, the pedal controller and the brake master controller control the electromagnetic isolation valve and the two-way three-way valve to return to their original positions, and the master cylinder will conduct the front-wheel servo brake cylinder, and the driver steps on the brake pedal to form a braking force.

[0022] Furthermore, in the above method, the specific process of the front-wheel servo brake cylinder is as follows: the motor drives the ball screw to rotate, so as to realize the linear movement of the nut, and further push the piston to move in the direction of the second cavity; by closing the liquid filling hole and compressing the volume of the second cavity, the boosting of the front-wheel servo brake cylinder is realized;

[0023] In the case where the controller of the front-wheel servo brake cylinder or the rear-wheel side brake fails or loses power, the manual cylinder communicates with the backup hole through a two-way three-way valve; when the driver steps on the brake pedal, the brake fluid in the manual cylinder flows into the first cavity of the electric cylinder housing through the two-way three-way valve and the backup hole, pushing the piston to the left, thereby increasing the pressure in the second cavity and the brake wheel cylinder, forming a manual backup braking force.

[0024] As another technical solution of the present invention, a distributed braking system for an automobile is composed of a liquid storage tank, a brake pedal, a manual cylinder, an electromagnetic isolation valve, a two-way three-way valve, a pedal force simulation device, a pedal controller, a main brake controller, a front-wheel servo brake cylinder, a rear-wheel servo brake cylinder, sensors, and brake wheel cylinders. The sensors include a pedal travel sensor, a master cylinder pressure sensor, a wheel cylinder pressure sensor, and a wheel speed sensor.

[0025] The manual cylinder adopts a double-cylinder structure, and its interior is divided into two sealed cavities by two pistons; the brake pedal is connected to the piston in the manual cylinder; the first cavity of the manual cylinder is connected to the liquid storage tank through a hydraulic pipeline; the second cavity of the manual cylinder is connected to the electromagnetic isolation valve through a hydraulic pipeline, and the electromagnetic isolation valve is respectively connected to the pedal force simulation device through a hydraulic pipeline. The pedal force simulation device, the front-wheel servo brake cylinder, and the rear-wheel servo brake cylinder are all connected to the liquid storage tank through hydraulic pipelines; the two-way three-way valve is respectively connected to the second cavity of the manual cylinder, the liquid storage tank, and the front-wheel servo brake cylinder through hydraulic pipelines; the rear-wheel servo brake cylinder is connected to the first cavity of the manual cylinder through an isolation valve through a hydraulic pipeline; brake wheel cylinders are respectively provided at the wheel ends of the two front wheels and the two rear wheels; the front-wheel servo brake cylinder and the rear-wheel servo brake cylinder are respectively connected to the brake wheel cylinders of the corresponding front wheels through hydraulic pipelines.

[0026] The pedal travel sensor and the master cylinder pressure sensor are respectively used to detect the travel data of the brake pedal and the pressure data of the manual cylinder; the wheel cylinder pressure sensor is used to measure the pressure data of the front-wheel servo brake cylinder and the rear-wheel servo brake cylinder; the wheel speed sensor is respectively used to measure the wheel speed data of the tires; the controller of the front-wheel servo brake cylinder is respectively connected to the wheel cylinder pressure sensor and the wheel speed sensor of the corresponding front wheel through signal lines, and the controller of the rear-wheel servo brake cylinder is respectively connected to the wheel cylinder pressure sensor and the wheel speed sensor of the corresponding rear wheel through signal lines.

[0027] The pedal controller is respectively connected to the pedal travel sensor, the master cylinder pressure sensor, the electromagnetic isolation valve, the two-way three-way valve, the controller of the front-wheel servo brake cylinder, and the controller of the rear-wheel servo brake cylinder through signal lines. The main brake controller is respectively connected to the controller of the front-wheel servo brake cylinder and the controller of the rear-wheel servo brake cylinder through signal lines. A data bus is connected between the pedal controller and the main brake controller.

[0028] Furthermore, both the front-wheel servo brake cylinder and the rear-wheel servo brake cylinder include an electric cylinder housing, a ball screw, a nut, a return spring with pre-tension, a guide pin, and a motor; the electric cylinder housing forms a first cavity and a second cavity that are isolated from each other through a piston, the ball screw and the nut are arranged in the first cavity, the nut is matched with the ball screw, the motor is connected to the ball screw and can drive the ball screw to rotate, and the ball screw can drive the nut to move linearly; the return spring is arranged in the second cavity of the electric cylinder housing, and its two ends respectively abut against the piston and the inner wall of the electric cylinder housing; four holes for the flow of brake fluid are provided on the electric cylinder housing; the first hole communicates with the second cavity of the electric cylinder housing and forms a braking circuit with the brake wheel cylinder; the second hole is used to install a wheel cylinder pressure sensor for the controller to collect the circuit pressure; the third hole is a fluid replenishing hole for connecting with a liquid storage tank; the fourth hole is a backup hole that communicates with the first cavity of the electric cylinder housing, and the backup hole of the front-wheel servo brake cylinder is connected to the second cavity of the master cylinder through a two-position three-way valve; the backup hole of the rear-wheel side servo brake cylinder is connected to the first cavity of the master cylinder through an isolation valve; the guide pin is used to limit the nut from rotating in the first cavity of the electric cylinder housing.

[0029] The beneficial effects of the present invention are as follows:

[0030] 1. In the present invention, the front-wheel servo brake cylinder and the rear-wheel side brake are close to the brake wheel cylinder, which can shorten the decompression time and make the braking response fast.

[0031] 2. In the present invention, the pressure building circuit of the servo brake cylinder does not have a solenoid valve, and the motor is directly used for braking pressure building, which can make the pressure building more direct and the adjustment simple.

[0032] 3. The braking system of the present invention has multiple actuators (front-wheel servo brake cylinder and rear-wheel side brake / rear-wheel servo brake cylinder) located at the wheel sides of each wheel, so that the braking forces of all wheels can be independently controlled and adjusted.

[0033] 4. In the present invention, the hole positions and cylinder body design of the servo brake cylinder can ensure that the main cylinder liquid injection hole is not blocked in the manual backup mode, avoiding the situation of manual backup failure.

[0034] 5. The braking system of the present invention can integrate functions such as electronic parking brake, simplifying the complexity of the braking system.

[0035] 6. The four braking circuits of the braking system of the present invention are independent of each other and redundant with each other, so the braking has high reliability and strong failure protection ability. Description of the Drawings

[0036] Figure 1 It is a schematic structural diagram of the distributed braking system of the vehicle in Embodiment 1 of the present invention;

[0037] Figure 2 It is a schematic structural diagram of the front-wheel servo brake cylinder in Embodiment 1 of the present invention;

[0038] Figure 3 It is a schematic diagram of the pressurization state when the front-wheel servo brake cylinder in Embodiment 1 of the present invention is working normally;

[0039] Figure 4 It is a working schematic diagram of the front-wheel servo brake cylinder under manual backup pressurization in Embodiment 1 of the present invention;

[0040] Figure 5 It is a schematic structural diagram of the distributed braking system of an automobile in Embodiment 2 of the present invention. Specific embodiments

[0041] The present invention will be further described below in conjunction with the accompanying drawings. It should be noted that this embodiment is based on the present technical solution and gives detailed implementation manners and specific operation processes, but the protection scope of the present invention is not limited to this embodiment.

[0042] Embodiment 1

[0043] This embodiment provides a distributed braking system for an automobile, as Figure 1 shown, which is composed of a liquid storage tank 1, a brake pedal 2, a manual cylinder 4, an electromagnetic isolation valve 6, a two-position three-way valve 7, a pedal force feeling simulation device 8, a pedal controller 9a, a brake main controller 9b, front-wheel servo brake cylinders 10a and 10b, rear-wheel side brakes 11a and 11b (which can be electromechanical brakes), sensors, and brake wheel cylinders 15a, 15b, 15c, and 15d. The sensors include a pedal travel sensor 3, a master cylinder pressure sensor 5, wheel cylinder pressure sensors 12a and 12b, wheel speed sensors 13a, 13b, 13c, and 13d, and force sensors 14a and 14b;

[0044] The brake pedal 2 is connected to the piston in the manual cylinder 4, and the manual cylinder 4 is connected to the liquid storage tank 1 through a hydraulic pipeline; the manual cylinder 4 is connected to the electromagnetic isolation valve 6 through a hydraulic pipeline, the electromagnetic isolation valve 6 is respectively connected to the pedal force feeling simulation device 8 through a hydraulic pipeline, and the pedal force feeling simulation device 8 and the front-wheel servo brake cylinders 10a and 10b are connected to the liquid storage tank 1 through a hydraulic pipeline; the two-position three-way valve 7 is respectively connected to the manual cylinder 4, the liquid storage tank 1, and the front-wheel servo brake cylinders 10a and 10b through a hydraulic pipeline; rear-wheel side brakes 11a and 11b are respectively arranged on the two rear wheels, and brake wheel cylinders 15a, 15b, 15c, and 15d are respectively arranged at the wheel ends of the two front wheels and the two rear wheels; the front-wheel servo brake cylinders 10a and 10b are respectively connected to the corresponding front-wheel brake wheel cylinders 15a and 15b through a hydraulic pipeline;

[0045] The pedal travel sensor 3 and the master cylinder pressure sensor 5 are respectively used to detect the travel data of the brake pedal 2 and the pressure data of the manual cylinder 4; the wheel cylinder pressure sensors 12a and 12b are used to measure the pressure data of the front wheel servo brake cylinders 10a and 10b; the wheel speed sensors 13a, 13b, 13c and 13d are respectively used to measure the wheel speed data of the two front wheels and the two rear wheels; the force sensors 14a and 14b are used to measure the braking forces of the brake cylinders 15c and 15d of the two rear wheels. The controllers of the front wheel servo brake cylinders 10a and 10b are respectively connected to the corresponding wheel cylinder pressure sensors 12a and 12b and the wheel speed sensors 13a and 13b of the front wheels through signal lines, and the controllers of the rear wheel side brakes 11a and 11b are respectively connected to the corresponding wheel speed sensors 13c and 13d and the force sensors 14a and 14b of the rear wheels through signal lines;

[0046] The pedal controller 9a is respectively connected to the pedal travel sensor 3, the master cylinder pressure sensor 5, the electromagnetic isolation valve 6, the two-way three-way valve 7, the controllers of the front wheel servo brake cylinders 10a and 10b, and the controllers of the rear wheel side brakes 11a and 11b through signal lines. The brake master controller 9b is respectively connected to the controllers of the front wheel servo brake cylinders 10a and 10b and the controllers of the rear wheel side brakes 11a and 11b through signal lines. The pedal controller 9a and the brake master controller 9b are connected through a data bus through signal lines.

[0047] It should be noted that in this embodiment, the number of servo brake cylinders is 2, and it is preferably arranged at the wheel sides of the left front wheel and the right front wheel (but not necessarily at the wheel ends), as Figure 1 shown.

[0048] In this embodiment, the brake master controller 9b is also communicatively connected to other electronic control systems of the vehicle.

[0049] As Figure 1 shown, when working normally, the driver steps on the brake pedal 2, and the pedal controller 9a controls the electromagnetic isolation valve 6 to conduct, and the two-way three-way valve 7 conducts the liquid storage tank and the front wheel servo brake cylinder, so that the brake pedal 2 is conducted with the pedal force feeling simulation device 8, and the driver obtains the pedal force through the pedal force feeling simulation device 8. The brake master controller 9b obtains the travel data detected by the pedal travel sensor 3 and the pressure data measured by the pressure sensor 5 from the pedal controller 9a, and identifies the driver's braking intention based on this, and then transmits the instruction to the controllers of the front wheel servo brake cylinders 10a and 10b and the controllers of the rear wheel side brakes 11a and 11b through electrical signals to control their respective pressurization actions, so as to obtain fast and uniform braking forces.

[0050] The target pressures at the wheel ends of each front wheel and each rear wheel are different, and the front-wheel servo brake cylinders and the rear-wheel brakes work independently. Therefore, functions such as anti-lock braking (ABS) and yaw stability control (ESC) can be achieved.

[0051] When the pedal controller 9a fails, the electromagnetic isolation valve 6 closes, the two-way three-way valve 7 conducts, and the master cylinder 4 conducts the front-wheel servo brake cylinders 10a and 10b. The driver's pedal force can be transmitted to the front-wheel servo brake cylinders 10a and 10b. At this time, the brake main controller 9b obtains the driver's braking intention based on the pressure data measured by the wheel cylinder pressure sensors 12a and 12b of the front-wheel servo brake cylinders 10a and 10b. The brake main controller 9b controls the rear-wheel brakes 11a and 11b to perform a certain degree of braking force control according to the driving intention, so as to achieve a greater braking force compared to the full failure.

[0052] When the brake main controller 9b fails, the system will not be able to communicate with other controllers of the vehicle to achieve functions such as coordinated kinetic energy recovery. However, the driver's intention can still be obtained by the pedal controller 9a; at this time, the controllers of the front-wheel servo brake cylinders 10a and 10b and the controllers of the rear-wheel brakes 11a and 11b still communicate with the pedal controller 9a, and the pedal controller 9a realizes the braking control.

[0053] The controllers of the front servo brake cylinders 10a and 10b and the controllers of the rear-wheel brakes 11a and 11b are redundant to each other. Therefore, when one of the controllers of the front-wheel servo brake cylinders 10a and 10b and the controllers of the rear-wheel brakes 11a and 11b fails, the brake main controller 9b will coordinate the remaining front-wheel servo brake cylinders and rear-wheel brakes that can still work to perform braking and balance the yaw torque.

[0054] In this embodiment, the controllers of the front-wheel servo brake cylinders 10a and 10b and the controllers of the rear-wheel brakes 11a and 11b can be powered by multiple independent power supplies. As a better solution, when the pedal controller 9a and the brake main controller 9b are completely powered off for the controllers of the front-wheel servo brake cylinders 10a and 10b and the rear-wheel brakes 11a and 11b, the electromagnetic isolation valve 6 and the two-way three-way valve 7 are controlled to return to their original positions, and the master cylinder 4 will conduct the front-wheel servo brake cylinders 10a and 10b, and the driver steps on the brake pedal 2 to form a braking force.

[0055] In this embodiment, such as Figure 2As shown, the front-wheel servo brake cylinders 10a and 10b include an electric cylinder housing, a ball screw 107, a nut 106, a return spring 105 with pre-tension, a guide pin 108, and a motor 109; the electric cylinder housing forms a first cavity and a second cavity that are isolated from each other through a piston 104, the ball screw 107 and the nut 106 are arranged in the first cavity, the nut 106 and the ball screw 107 cooperate with each other, the motor 109 is connected to the ball screw 107 and can drive the ball screw 107 to rotate, and the ball screw 107 can drive the nut 106 to move linearly; the return spring 105 is arranged in the second cavity, and its two ends are respectively abutted against the piston and the inner wall of the electric cylinder housing; four holes 100, 101, 102, and 103 for the flow of brake fluid are provided on the electric cylinder housing; the first hole 100 communicates with the second cavity and forms a brake circuit with the brake wheel cylinder; the second hole 101 is used for installing a wheel cylinder pressure sensor for the controller to collect the circuit pressure; the third hole 102 is a liquid replenishing hole for connecting with the liquid storage tank 1; the fourth hole 103 is a backup hole that communicates with the first cavity and is connected to the manual cylinder 4 through a two-position three-way valve 7; the guide pin 108 is used to limit the nut 106 from rotating in the first cavity.

[0056] During normal operation, the motor 109 is driven to rotate the ball screw 107, thereby realizing the linear movement of the nut 106, and further pushing the piston 104 in the direction of the second cavity; by closing the liquid replenishing hole and compressing the volume of the second cavity, the pressure increase of the front-wheel servo brake cylinder is realized. As Figure 3 shown.

[0057] In the case where the controller of the front-wheel servo brake cylinder or the rear-wheel side brake fails or loses power, the manual cylinder 4 is connected to the backup hole through the two-position three-way valve 7. When the driver steps on the brake pedal 2, the brake fluid in the manual cylinder 4 flows into the first cavity of the electric cylinder housing through the two-position three-way valve 7 and the backup hole, pushing the piston 104 to the left, and further increasing the pressure in the second cavity and the brake wheel cylinder, forming a manual backup braking force. As Figure 4 shown.

[0058] Embodiment 2

[0059] This embodiment provides a distributed braking system for an automobile. As Figure 5 shown, it consists of a liquid storage tank 1, a brake pedal 2, a manual cylinder 4, an electromagnetic isolation valve 6, a two-position three-way valve 7, a pedal force simulation device 8, a pedal controller 9a, a main brake controller 9b, front-wheel servo brake cylinders 10a and 10b, rear-wheel servo brake cylinders 10c and 10d, sensors, and brake wheel cylinders 15a, 15b, 15c, and 15d. The sensors include a pedal travel sensor 3, a master cylinder pressure sensor 5, wheel cylinder pressure sensors 12a, 12b, 12c, and 12d, and wheel speed sensors 13a, 13b, 13c, and 13d;

[0060] The manual cylinder 4 adopts a double-cylinder structure, and its interior is divided into two sealed cavities by two pistons; the brake pedal 2 is connected to the piston inside the manual cylinder 4; the first cavity and the second cavity of the manual cylinder 4 are respectively connected to the liquid storage tank 1 through hydraulic pipelines; the second cavity of the manual cylinder 4 is connected to the electromagnetic isolation valve 6 through a hydraulic pipeline, the electromagnetic isolation valve 6 is respectively connected to the pedal force simulation device 8 through a hydraulic pipeline, and the pedal force simulation device 8, the front-wheel servo brake cylinders 10a and 10b, and the rear-wheel servo brake cylinders 10c and 10d are all connected to the liquid storage tank 1 through hydraulic pipelines; the two-position three-way valve 7 is respectively connected to the second cavity of the manual cylinder 4, the liquid storage tank 1, and the front-wheel servo brake cylinders 10a and 10b through hydraulic pipelines; the rear-wheel servo brake cylinders 10c and 10d are both connected to the first cavity of the manual cylinder 4 through the isolation valve 15 through a hydraulic pipeline; brake wheel cylinders 15a, 15b, 15c, and 15d are respectively provided at the wheel ends of the two front wheels and the two rear wheels; the front-wheel servo brake cylinders 10a and 10b and the rear-wheel servo brake cylinders 10c and 10d are respectively connected to the corresponding brake wheel cylinders 15a, 15b, 15c, and 15d of the front wheels through hydraulic pipelines;

[0061] The pedal travel sensor 3 and the master cylinder pressure sensor 5 are respectively used to detect the travel data of the brake pedal 2 and the pressure data of the manual cylinder 4; the wheel cylinder pressure sensors 12a, 12b, 12c, and 12d are used to measure the pressure data of the front-wheel servo brake cylinders 10a and 10b and the rear-wheel servo brake cylinders 10c and 10d; the wheel speed sensors 13a, 13b, 13c, and 13d are respectively used to measure the wheel speed data of the two front wheels and the two rear wheels; the controllers of the front-wheel servo brake cylinders 10a and 10b are respectively connected to the corresponding wheel cylinder pressure sensors 12a and 12b of the front wheels and the wheel speed sensors 13a and 13b through signal lines, and the controllers of the rear-wheel servo brake cylinders 10c and 10d are respectively connected to the corresponding wheel cylinder pressure sensors 12c and 12d of the rear wheels and the wheel speed sensors 13c and 13d through signal lines;

[0062] The pedal controller 9a is respectively connected to the pedal travel sensor 3, the master cylinder pressure sensor 5, the electromagnetic isolation valve 6, the two-position three-way valve 7, the controllers of the front-wheel servo brake cylinders 10a and 10b, and the controllers of the rear-wheel servo brake cylinders 10c and 10d through signal lines, the brake master controller 9b is respectively connected to the controllers of the front-wheel servo brake cylinders 10a and 10b and the controllers of the rear-wheel servo brake cylinders 10c and 10d through signal lines, and the pedal controller 9a and the brake master controller 9b are connected through a data bus through signal lines.

[0063] The difference between the system of this embodiment and that of Embodiment 1 lies in that the number of servo brake cylinders is 4, that is, servo brake cylinders with the same structure are provided on the wheel ends of both the two front wheels and the two rear wheels. At this time, a hydraulic circuit is additionally provided for the rear wheels, and its on-off is controlled by the isolation valve 15. The manual cylinder 4 is also changed to a dual-chamber master cylinder. The working process is basically the same as that of Embodiment 1. The main difference is that when the controllers of the front-wheel servo brake cylinders 10a and 10b and the front-wheel servo brake cylinders 10c and 10d are all powered off, the electromagnetic isolation valve 6 and the two-way three-way valve 7 return to their original positions, and the manual cylinder 4 will fully conduct the front-wheel servo brake cylinders 10a and 10b and the front-wheel servo brake cylinders 10c and 10d, and the driver steps on the brake pedal 2 to generate braking force.

[0064] In this embodiment, as Figure 2 shown, the front-wheel servo brake cylinders 10a and 10b and the rear-wheel servo brake cylinders 10c and 10d each include an electric cylinder housing, a ball screw 107, a nut 106, a return spring 105 with preload, a guide pin 108, and a motor 109; the electric cylinder housing forms a first cavity and a second cavity isolated from each other through a piston 104, the ball screw 107 and the nut 106 are arranged in the first cavity, the nut 106 is matched with the ball screw 107, the motor 109 is connected to the ball screw 107 and can drive the ball screw 107 to rotate, and the ball screw 107 can drive the nut 106 to move linearly; four holes 100, 101, 102, and 103 for the flow of brake fluid are provided on the electric cylinder housing; the first hole 100 communicates with the second cavity of the electric cylinder housing to form a braking circuit with the brake wheel cylinder; the second hole 101 is used for installing a wheel cylinder pressure sensor for the controller to collect the circuit pressure; the third hole 102 is a liquid replenishing hole for connecting with the liquid storage tank 1; the fourth hole 103 is a backup hole which communicates with the first cavity of the electric cylinder housing, and the front-wheel servo brake cylinders 10a and 10b are connected to the second cavity of the manual cylinder 4 through the two-way three-way valve 7; the backup holes of the rear-wheel side servo brake cylinders 10c and 10d are connected to the first cavity of the manual cylinder 4 through the isolation valve 15; the guide pin 108 is used to limit the nut 106 from rotating in the first cavity of the electric cylinder housing.

[0065] For those skilled in the art, various corresponding changes and deformations can be given according to the above technical solutions and concepts, and all such changes and deformations should be included within the protection scope of the claims of the present invention.

Claims

1. A distributed braking system for an automobile, characterized in that, It consists of a liquid storage tank, a brake pedal, a master cylinder, an electromagnetic isolation valve, a two-position three-way valve, a pedal force feel simulation device, a pedal controller, a brake master controller, a front-wheel servo brake cylinder, a rear-wheel hub brake, sensors and a brake wheel cylinder. The sensors include a pedal travel sensor, a master cylinder pressure sensor, an inertial measurement unit, a wheel cylinder pressure sensor, a wheel speed sensor and a force sensor; The brake pedal is connected to the piston in the master cylinder, and the master cylinder is connected to the liquid storage tank through a hydraulic pipeline; the master cylinder is connected to the electromagnetic isolation valve through a hydraulic pipeline, the electromagnetic isolation valve is respectively connected to the pedal force feel simulation device through a hydraulic pipeline, and the pedal force feel simulation device and the front-wheel servo brake cylinder are connected to the liquid storage tank through a hydraulic pipeline; the two-position three-way valve is respectively connected to the master cylinder, the liquid storage tank and the front-wheel servo brake cylinder through a hydraulic pipeline; rear-wheel hub brakes are respectively arranged on the wheel hubs of the two rear wheels, and brake wheel cylinders are respectively arranged on the wheel ends of the two front wheels and the two rear wheels; each front-wheel servo brake cylinder is connected to the brake wheel cylinder of the corresponding front wheel through a hydraulic pipeline; The pedal travel sensor and the master cylinder pressure sensor are respectively used to detect the travel data of the brake pedal and the pressure data of the master cylinder; the inertial measurement unit is used to monitor the acceleration and angular acceleration of the vehicle in all directions; the wheel cylinder pressure sensor is used to measure the pressure data of each front-wheel servo brake cylinder; the wheel speed sensor is respectively used to measure the wheel speed data of the tires; the force sensor is used to measure the braking force of the rear-wheel hub brakes of the two rear wheels; the controllers of each front-wheel servo brake cylinder are respectively connected to the wheel cylinder pressure sensor and the wheel speed sensor of the corresponding front wheel through signal lines, and the controllers of the rear-wheel hub brakes are respectively connected to the wheel speed sensor and the force sensor of the corresponding rear wheel through signal lines; The pedal controller is respectively connected to the pedal travel sensor, the master cylinder pressure sensor, the electromagnetic isolation valve, the two-position three-way valve, the controller of the front-wheel servo brake cylinder and the controller of the rear-wheel hub brake through signal lines, the brake master controller is respectively connected to the controller of the front-wheel servo brake cylinder and the controller of the rear-wheel hub brake through signal lines, and the pedal controller and the brake master controller are connected through a data bus.

2. The system according to claim 1, characterized in that, The rear-wheel hub brake adopts an electromechanical brake.

3. The system according to claim 1, characterized in that, The front-wheel servo brake cylinder includes an electric cylinder housing, a ball screw, a nut, a return spring with pre-tension, a guide pin, and a motor; the electric cylinder housing forms a first cavity and a second cavity that are isolated from each other through a piston, the ball screw and the nut are arranged in the first cavity of the electric cylinder housing, the nut is matched with the ball screw, the motor is connected to the ball screw and can drive the ball screw to rotate, and the ball screw can drive the nut to move linearly; the return spring is arranged in the second cavity of the electric cylinder housing, and its two ends respectively abut against the piston and the inner wall of the electric cylinder housing; four holes for the flow of brake fluid are provided on the electric cylinder housing; the first hole communicates with the second cavity of the electric cylinder housing and forms a braking circuit with the brake wheel cylinder; the second hole is used for installing a wheel cylinder pressure sensor for the controller to collect the circuit pressure; the third hole is a liquid replenishing hole for connecting with a liquid storage tank; the fourth hole is a backup hole that communicates with the first cavity of the electric cylinder housing and is connected to a manual cylinder through a two-position three-way valve; the guide pin is used to limit the nut from rotating in the first cavity of the electric cylinder housing.

4. A working method for the system according to any one of claims 1 - 3, characterized in that, The specific process is as follows: During normal operation, when the driver steps on the brake pedal, the pedal controller controls the electromagnetic isolation valve to conduct, and the two-position three-way valve conducts the liquid storage tank and the front-wheel servo brake cylinder, so that the brake pedal and the pedal force feeling simulation device are conducted, and the driver obtains the pedal force through the pedal force feeling simulation device. The brake master controller obtains the stroke data detected by the pedal stroke sensor and the pressure data measured by the pressure sensor from the pedal controller, and based on this, identifies the driver's braking intention, and then transmits the instruction to the controller of the front-wheel servo brake cylinder and the controller of the rear-wheel side brake through an electric signal to control them to perform a boosting action respectively, so as to obtain a fast and uniform braking force. When the pedal controller fails, the electromagnetic isolation valve closes, and the two-position three-way valve conducts the manual cylinder and the front-wheel servo brake cylinder, and the driver's pedal force can be transmitted to the front-wheel servo brake cylinder; at this time, the brake master controller obtains the driver's braking intention according to the pressure data measured by the wheel cylinder pressure sensor of the front-wheel servo brake cylinder; the brake master controller controls the rear-wheel side brake to perform a certain degree of braking force control according to the driving intention to achieve a greater braking force compared to the full failure. When the brake master controller fails, the system will not be able to communicate with other controllers of the vehicle, but the driver's intention can still be obtained by the pedal controller; at this time, the controller of the front-wheel servo brake cylinder and the controller of the rear-wheel side brake still communicate with the pedal controller to jointly achieve braking control. The controller of the front-wheel servo brake cylinder and the controller of the rear-wheel side brake are redundant to each other. Therefore, when one or more of the controller of the front-wheel servo brake cylinder and the controller of the rear-wheel side brake fail, the brake master controller will coordinate the remaining front-wheel servo brake cylinders and rear-wheel side brakes that can still work to perform braking and balance the yaw torque.

5. The method according to claim 4, characterized in that, The controllers for the front-wheel servo brake cylinders and the rear-wheel side brakes can be powered by multiple independent power supplies; when all the controllers for the front-wheel servo brake cylinders and the rear-wheel side brakes are de-energized, the pedal controller and the master brake controller control the electromagnetic isolation valve and the two-way three-way valve to return to their original positions, and the manual cylinder will conduct the front-wheel servo brake cylinder, and the driver steps on the brake pedal to generate braking force.

6. The method according to claim 4, characterized in that, The specific process of the front-wheel servo brake cylinder is as follows: The ball screw is rotated by a motor, so as to realize the linear movement of the nut, and then the piston is pushed to move in the direction of the second cavity; by closing the liquid replenishing hole, the volume of the second cavity is compressed to increase the pressure of the front-wheel servo brake cylinder. When the controller of the front-wheel servo brake cylinder or the rear-wheel side brake is de-energized or fails, the manual cylinder communicates with the backup hole through the two-way three-way valve; when the driver steps on the brake pedal, the brake fluid in the manual cylinder flows into the first cavity of the electric cylinder housing through the two-way three-way valve and the backup hole, pushing the piston to the left, and then increasing the pressure in the second cavity and the brake wheel cylinder to form a manual backup braking force.

7. A distributed braking system for an automobile, characterized in that, It consists of a liquid storage tank, a brake pedal, a manual cylinder, an electromagnetic isolation valve, a two-way three-way valve, a pedal force simulation device, a pedal controller, a master brake controller, a front-wheel servo brake cylinder, a rear-wheel servo brake cylinder, sensors, and brake wheel cylinders; the sensors include a pedal travel sensor, a master cylinder pressure sensor, a wheel cylinder pressure sensor, and a wheel speed sensor. The manual cylinder adopts a double-cylinder structure, and its interior is divided into two sealed cavities by two pistons; the brake pedal is connected to the piston in the manual cylinder; the first cavity of the manual cylinder is connected to the liquid storage tank through a hydraulic pipeline; the second cavity of the manual cylinder is connected to the electromagnetic isolation valve through a hydraulic pipeline, and the electromagnetic isolation valve is respectively connected to the pedal force simulation device through a hydraulic pipeline, and the pedal force simulation device, the front-wheel servo brake cylinder, and the rear-wheel servo brake cylinder are all connected to the liquid storage tank through hydraulic pipelines; the two-way three-way valve is respectively connected to the second cavity of the manual cylinder, the liquid storage tank, and the front-wheel servo brake cylinder through hydraulic pipelines; the rear-wheel servo brake cylinder is connected to the first cavity of the manual cylinder through an isolation valve through a hydraulic pipeline; brake wheel cylinders are respectively provided at the wheel ends of the two front wheels and the two rear wheels; the front-wheel servo brake cylinder and the rear-wheel servo brake cylinder are respectively connected to the brake wheel cylinders of the corresponding front wheels through hydraulic pipelines. The pedal travel sensor and the master cylinder pressure sensor are respectively used to detect the travel data of the brake pedal and the pressure data of the manual cylinder; the wheel cylinder pressure sensor is used to measure the pressure data of the front-wheel servo brake cylinder and the rear-wheel servo brake cylinder; the wheel speed sensors are respectively used to measure the wheel speed data of the tires; the controller of the front-wheel servo brake cylinder is respectively connected to the wheel cylinder pressure sensor and the wheel speed sensor of the corresponding front wheel through signal lines, and the controller of the rear-wheel servo brake cylinder is respectively connected to the wheel cylinder pressure sensor and the wheel speed sensor of the corresponding rear wheel through signal lines. The pedal controller is respectively connected to a pedal travel sensor, a master cylinder pressure sensor, an electromagnetic isolation valve, a two-position three-way valve, the controllers of the front-wheel servo brake cylinder and the rear-wheel servo brake cylinder through signal lines. The brake master controller is respectively connected to the controllers of the front-wheel servo brake cylinder and the rear-wheel servo brake cylinder through signal lines. A data bus is connected between the pedal controller and the brake master controller.

8. The system according to claim 7, characterized in that, Both the front-wheel servo brake cylinder and the rear-wheel servo brake cylinder include an electric cylinder housing, a ball screw, a nut, a return spring with preload, a guide pin and a motor. The electric cylinder housing forms a first cavity and a second cavity isolated from each other through a piston. The ball screw and the nut are arranged in the first cavity. The nut is matched with the ball screw. The motor is connected to the ball screw and can drive the ball screw to rotate. The ball screw can drive the nut to move linearly. The return spring is arranged in the second cavity of the electric cylinder housing, and its two ends respectively abut against the piston and the inner wall of the electric cylinder housing. Four holes for the flow of brake fluid are provided on the electric cylinder housing. The first hole communicates with the second cavity of the electric cylinder housing and forms a brake circuit with the brake wheel cylinder. The second hole is used for installing a wheel cylinder pressure sensor for the controller to collect the circuit pressure. The third hole is a liquid replenishing hole for connecting to a liquid storage tank. The fourth hole is a backup hole, which communicates with the first cavity of the electric cylinder housing. The backup hole of the front-wheel servo brake cylinder is connected to the second cavity of the master cylinder through a two-position three-way valve. The backup hole of the rear-wheel side servo brake cylinder is connected to the first cavity of the master cylinder through an isolation valve. The guide pin is used to limit the nut from rotating in the first cavity of the electric cylinder housing.

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